| gendef (n, X.LIVEIGN (_)) = ([SUCC (n+1)])
| gendef (n, X.LABEL l) = ([SUCC (n+1)])
| gendef (n, X.INSN(X.NV, _)) = ([SUCC (n+1)])
| gendef (n, X.LIVEIGN (_)) = ([SUCC (n+1)])
| gendef (n, X.LABEL l) = ([SUCC (n+1)])
| gendef (n, X.INSN(X.NV, _)) = ([SUCC (n+1)])